package ddth.dasp.framework.resource;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.lang3.StringUtils;

/**
 * This {@link IResourceLoader} loads resources from file system.
 * 
 * @author NBThanh <btnguyen2k@gmail.com>
 */
public class FsResourceLoader extends AbstractResourceLoader {

    private String rootDir;
    private String envNameRootDir;

    protected String getRootDir() {
        return rootDir;
    }

    public void setRootDir(String rootDir) {
        this.rootDir = rootDir;
    }

    /**
     * If {@link FsResourceLoader#envNameRootDir} is set, value of the
     * corresponding environment (if set) will be assigned to {@link #rootDir}.
     * 
     * @return
     */
    protected String getEnvNameRootDir() {
        return envNameRootDir;
    }

    /**
     * If {@link FsResourceLoader#envNameRootDir} is set, value of the
     * corresponding environment (if set) will be assigned to {@link #rootDir}.
     * 
     * @param envNameRootDir
     */
    public void setEnvNameRootDir(String envNameRootDir) {
        this.envNameRootDir = envNameRootDir;
    }

    public void init() {
        if (!StringUtils.isBlank(envNameRootDir)) {
            String value = System.getProperty(envNameRootDir);
            if (!StringUtils.isBlank(value)) {
                setRootDir(value);
            }
        }
    }

    public void destroy() {
        // EMPTY
    }

    protected File buildFile(String path) {
        return StringUtils.isBlank(rootDir) ? new File(path) : new File(rootDir, path);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public long getLastModified(String path) {
        File file = buildFile(path);
        return file.lastModified();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean resourceExists(String path) {
        File file = buildFile(path);
        return file.exists();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public InputStream loadResource(String path) throws IOException {
        File file = buildFile(path);
        if (file.exists()) {
            InputStream is = new FileInputStream(file);
            return is;
        }
        return null;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String[] getEntryPaths(String rootPath) throws IOException {
        File file = buildFile(rootPath);
        if (file.isFile()) {
            return new String[] { rootPath };
        }
        return file.list();
    }
}